1. Field of the Invention
This invention relates to a coil apparatus.
2. Description of the Related Art
Heretofore, a coil apparatus has been produced by binding a wiring around a bobbin to form a coil, transferring the coil to a client and then accommodating the coil in a yoke. A housing is molded around the coil by to prevent the winding from being broken during transport to the client and to enhance a high-impact property of the bobbin. An example of such a coil apparatus is disclosed in Japanese Patent Public Disclosure No. HEI 12-30961 (2000).
The molding method is carried out by setting the coil in a mold die and pouring a molten resin material into the mold die. The mold die, however, increases the cost of production.
In view of the above problem, an object of the present invention is to provide a coil apparatus that can protect a coil at a low cost.
The invention is directed to a coil apparatus comprising: a coil formed by binding a wiring around a bobbin; and a holding member having a substantially annular containing chamber adapted to accommodate the coil. The holding member includes a closing element for closing the containing chamber to cover the coil.
The closing element preferably includes a lid to be mounted on the containing chamber and secured to the holding member.
An elastic element may be disposed between the lid and the bobbin so that the elastic element is elastically compressed when the lid is mounted on the containing chamber.
A pair of seal rings may be disposed between opposed peripheral surfaces of the lid and containing chamber so that the containing chamber is sealed when the seal rings come into close contact with the opposed peripheral surfaces.
The closing element may include a potting material filled into and solidified in the containing chamber.
Anti-rotation means may be provided between the bobbin and the holding member to maintain the bobbin stationary relative to the holding member when the means are coupled to each other.
The containing chamber is closed by providing the closing element on the holding member to cover the coil after the coil has been accommodated in the containing chamber of the holding member. Thus, the coil is not exposed outwardly and is protected by the holding member and closing element.
The closing element closes the containing chamber. Thus, it is possible to protect the coil at a low cost in comparison with the prior art coil apparatus in which the housing is formed by molding with the mold die.
The lid is mounted on and secured to the holding member after the coil is accommodated in the containing chamber. Thus, the holding member and lid cover the coil.
The elastic member is compressed elastically between the lid body and the bobbin. Therefore, it is possible to hold the coil with no play between the coil and the holding member and between the coil and the lid.
A pair of seal rings seal the containing chamber. As a result, it is possible to prevent external liquid from entering the containing chamber.
The potting material is injected into the containing chamber after the coil has been accommodated in the containing chamber and the coil is fixed in the containing chamber when the potting material is solidified. Accordingly, it is possible to restrict a relative displacement in the peripheral direction between the bobbin and the holding member and to maintain them at an anti-rotation position.
The foregoing and other features of the present invention will become apparent to one skilled in the art to which the present invention relates upon consideration of the invention with reference to the accompanying drawings.